Light lock for the entrance/exit passageway of a container for light-sensitive material



United States Patent [56] References Cited UNITED STATES PATENTS [72]Inventors PaulJ. Fleming;

Arthur C. Rissber'ger, Jr., and Lawrence A. Ulmschneider, Rochester, NewYork 7 ,om 5m 95 9 n 0 t s 0 B R S. a m m o h m T. d mmn m. MM S 0 TemeHlm. mmm Mm oee na RHB hun 4 0. 694 .J W 346 t 999 mr lill ne D 902 U0.l1 "R a x 457 ES 425 yy .#2,3 re 649 wm 585 n0 0,4,1 .nn 223 PA v. m..m u D. J mmm CYN k f 7 awo 60.MNn 97 .m 19K-...94m inne M0 ,an-0. zsmepnvhm sooc 6NNER8 a de N wm In. ab Wmn as AFPA .11.111 1253 2247 [[.lrl

Patented Nov. 3, 1970 3,537,376

' Sheet l 0T2 PAUL J. FLEMING l ARTHUR C. RlSSBERGR JR. ,2 LAWRENCE A.ULMSCHNEIDER INVENTORS KW fard) M A LIGHT LOCK FOR TIIE ENTRANCE/EXITPASSAGEWAY l. Field of the Invention This invention relates to a lightlock for containers for lightsensitive materials and in a preferredembodiment to a light lock for the film gate of a photographic filmcartridge.

2. Description of the Prior Art To prevent light from entering throughthe lips of a conventional photographic film and/or paper magazine, itis customary to attach fabric of various types to the lips. The fabriccloses the opening, but" is resilient enough to allow thelight-sensitive material to pass through. This method of light locking,unfortunately, results in loose fabric particles depositing on the film.Also, variations in lip opening and fabric thickness and resiliencecombine to result in a wide range of pull-out forces.

SUMMARY OF THE INVENTION It is an object of the present invention toprovide a light lock for the entrance and/or exit passageway of acontainer for light-sensitive material which light lock eliminates thedirt problem, provides a low, uniform, pull-out force, maintainslighttightness regardless of the normal variations in width of thepassageway and reduces manufacturing cost.

These and other objects of the present invention are accomplished asfollows. The pair of lips defining the container entrance or exitpassageway are covered with a layer of foamcloth laminate. The pad, orlayer attached to the upper lip, is attached at both the front and rearedges while the flap, or layer attached to the lower lip, is attachedalong a single longitudinal line, preferably closer to the front edge ofthe lower lip than to the rear edge. The lines of attachment of the padand the flap terminate short of the side walls of the passageway wherebythe layer bulges toward the opposite lip to ensure an effective lightlock at the sides of the passageway. In another embodiment the pad andflap can be sealed over the entire area from edge to edge and side wallto side wall. The inwardly extending free end of' the flap mayextend'into the chamber. This free end can be square cut although it ispreferably hemmed or pinched to aid in assuring a low, uniform pull-outforce and to reduce the generation of dirt particles as thelight-sensitive material passes over the free end. The pad and f'lap aresufficiently thick so as to cooperate to provide a light lock across theheight of the passageway.

The width of the flap and pad is greater than the width of anyvperforation which may be provided in the light-sensitive material. Inthe case of a cartridge for roll film, the inwardly extending end of theflap is urged toward the upper lip by the outer convolution of the roll,especially when in clock-spring condition, to add to the effectivenessof the light lock.

BRIEF DESCRIPTION OF THE DRAWINGS These and other objects of the presentinvention will be more fully understood by reference to the followingdetailed description when read in conjunction with the attacheddrawings, in which like reference numerals refer to like elements, andin which:

FIG. l is a perspective view of a cartridge provided with the light lockof the present invention;

FIGS. 2-5 are enlarged cross-sectional views through the film gate of acartridge such as is shown in FIG. 1 showing various embodiments of thepresent invention;

FIG. 6 is a cross-sectionalview through the cartridge of FIG. l showinga light lock according to another embodiment ofthe present invention;

FIG. 7 is a perspective view of the bottom half of the cartridge of FIG.l with the flap ofFlG. 2 attached; and

FIG. 8 is a perspective view of the top half of the cartridge of FIG.'1with the pad of FIG. 2 attached.

DESCRIPTION 0F THE PREFERRED EMBODIMENTS The light lock of the presentinvention will be described below by reference to its use in a cartridge2 for roll film 4. It is to be understood, however, that the light lockof the present invention is not limited in use to this particularapplication but is useful in any type of container for light-sensitivematerial. The container can be a cassette, cartridge, magazine, box;etc., and the material can be roll film, sheet film, photographic paper,or any other light-sensitive material. Referring first to theembodimentsshown in FIGS. 2-4, the light lock of the present invention will be seento comprise a pad 6 attached to the upper lip 8 of the film gate l0 anda flap attached to the lower lip 12 of the gate.

The differences between the three embodiments shown in FIGS. 2-4 aredifferences in the flap. In all three embodiments the pad 6 isidentical. Both the pad 6 and the flap are constructed of a flexiblelayer 14 of material, such as polyurethane foam, laminated to a facinglayer 16 of material having a low coefficient of friction such as nyloncloth. When using the above-named materials, they are preferablyflamelaminated together, although other adhesive methods can be used.The pad 6 can be attached to the upper lip 8 by any convenient attachingmethod. Whatever method is used it is preferred that the front and rearedges of the pad have the facing layer 16 curved upwardly toward theupper lip 8 to provide a smooth surface across which the strip of filmcan pass when leaving the cartridge. By providing such a smooth surfacehaving no rough edges, the generation of dirt particles is reduced andthe pull-out force is reduced and made more uniform. The remainingcentral portion of the pad 6 bulges toward the lower lip l2. Theflexible layer 14 has sufficient thickness (greater than half the heightof the film gate passageway) to provide, in cooperation with the flap'tobe described hereinafter', an effective light lock for the film gate ofthe cartridge.

In the embodiment shown in FIG. 2, the flap 18 is attached to the lowerlip l2 along a single longitudinal line 20 which is substantiallyparallel to and adjacent the front edge l22 of the lower lip l2 butpreferably spaced rearwardly (or inwardly) a short`distance therefrom.By so attaching the flap I8' at a point intermediate its longitudinal(inner and outer) edges 24 and 26, the edges 24 and 26 are free andunattached to the lip l2. This construction not only simplifiesmanufacture and reduces manufacturing cost, it also provides a flaphaving alarge area of contact with the film 4 in the film gate 10whereby the light lock is made as effective as is possible.

ln the embodiment of FIG. 2 the inwardly extending edge 24 of the flapI8 projects into the chamber 28. This construction takes advantage ofthe small, unused space in the chamber 28 to increase the area ofcontact between the flap 18 and the film 4 and to thus increase theeffectiveness of the light lock of the present invention. As shown inFIG. 2 the outer convolution of the roll of film contained in thechamber 28 is in contact with the free edge 24 of the flap. This outerconvolution compresses the foam layer 14 thus urging the edge 24 of theflap upwardly toward the upper lip 8. This feature, along with theextended length of the flap, adds to the llght locltlng effectiveness ofthe light lock of the present invention.

The embodiments shown in FIGS. 3 and 4 are similar to the embodimentshown in FIG. 2 but are modifications thereof. One problem which may beassociated with the embodiment of FIG. 2, at least when the flap doesextend somewhat into the chamber 28, is that as the strip of film ispulled out of the cartridge the perforations in the film may tend tocatch on the free edge 24 of the flap and possibly generate dirtparticles. Another possible problem with the embodiment shown in FIG. 2is that the outer convolution 30 of the roll of film rides across thesurface of the polyurethane foam, which foam has a coefficient offriction which is somewhat higher than that of the nylon facing, thusincreasing the pull-out forces in the system. The friction generatedbetween the foam and the outer convolution of film may tend todelaminatethe flap I8 and may also pull the free edge 24 ofthe flapdownwardly with the rotating outer convolution 30 of the film thusproducing a build-up of the flap material which could jam the system.

The embodiments shown in FIGS. 3 and 4 overcome the above-mentionedpossible disadvantages in the embodiment of FIG. 2. FIG. 3 shows a flap32 attached to the very front edge 22 of the lower lip l2. The flap 32extends a short distance into the chamber 28. The free edge 34 of theflap has been hemmed to eliminate any rough edge and to put the facinglayer in contact with the outer convolution 30 of the film in thechamber 28. The hem 33 can be achieved by turning the facing layeraround and under and sealing the end, for example, ultrasonically.

FIG. 4 shows a flap 36 which is similar to the flap 32 of FIG. 3 exceptthat its free edge 38 has been pinched. This embodiment, depending onthe length which the flap 36 extends into the lchamber 28, eliminates atleast one of the above-men tioned problems; that is, the generation ofdirt particles. This is because the outgoing strip of film does notslide over the edge 38 but rather bridges over the edge as shown.However, depending upon the length which the flap extends into thechamber 28, the construction of FIG. 4 may or may not overcome theabove-mentioned problem with respect to the friction generated betweenthe' polyurethane foam and the outer convolution 30 of the film.

In the embodiment ofFIG. the pad has been eliminated by making thethickness of the hemmed flap 40 sufficient to fill up the entire heightof the passageway or film gate 10. This embodiment can use any of theflaps shown in FIGS. 2-4 and is useful when dirt is not a problem.However, it is usually desirable to provide the pad at the upper lip inorder to eliminate any defects in the final product which result fromdirt having collected on the film. The pad 6 of the present inventionnot only cooperates with the flap to providean effective light lock butalso operates to pick up and remove dirt from the back side of the filmas the film is wound back into the cartridge. This is important since asthe film is wound back into the chamber 24, the emulsion side of thefilm contacts the back side of the preceding convolution and any dirt onthe back side can be transferred to or abrade the emulsion and canresult in a defect in the finished product. y

Another light lock ofthe present invention (See FIG. 6) does not includea pad but employs a flap 42 formed as a single piece of semirigidplastic or other material. In this embodiment the fiap 42 is preferablyattached to the lower lip by being inserted permanently in a groove 44in the lower lip. In this embodiment there is no pad and no foam toclose the film gate. However, the usual need for a light lock is onlywhen the cartridge is out of the camera and completely filled with aroll of film (after the cartridge has been inserted into a camera,thetlight-tight housing of the camera provides the light lock for thefilm). The embodiment shown in FIG. 6 does provide an effective lightlock in this case as follows. The flap 42 is an effective light lock byvirtue of the fact that the outer convolu tion 30 of film urges thef'lap upwardly toward the emulsion surface of the strip of film in thefilm gate. The pressure on the flap from the outer convolution of theroll of film is enhanced due to the fact that the film usually exists ina clock-spring condition in the chamber 28. The inwardly extending edge46 of the flap 42 preferably terminates just short of the point of thetangency of the exiting film strip and the outer convolution 30. If theflap 42 is too short there may be insufficient pressure on the flap andinsufficient area of contact. If the flap is too long it may be cinchedand may bind between the convolutions of filmresulting in a jam or in anextremely high pull-out force.

FIGS'.4 7 and 8 are perspective views showing the lowe'r half 48 and theupper half 50 of the cartridge 2 with the pad 6 and the flap 18 of FIG.2 attached to the upper and lower lips respectively. As can be seen inFIGS. 7 and 8, the lines of attachment of the flap and pad to the lipsdo not extend across the entire width of the film gate or passageway butrather terminste just short of the side walls 48 and 50 thereof. By thismeans the flap and the pad are allowed to bulge away from theirrespective lips to provide an effective light lock at the sides of thefilm gate l0.

The material of which the flap and the pad can be made isv notrestricted to any particular materials. Other flexible materials can beused in place of the polyurethane foam and other facing materials of lowcoefficient of friction can be used in place of the nylon. For example,plastic, plastic foam,

cloth, paper, metal, rubber, etc., or a combination of such materialscan be used. The method of attaching the flap and the pad can be, forexample, molding, crimping, tacking, gluing, riveting, staking,ultrasonic sealing, dielectric sealing, heat sealing, etc. and thesealing area not confined to a line.

The invention has been described in detail with particular reference topreferred embodiments thereof, but it will be un derstood thatvariations and modifications can be effected within the spirit and scopeof the invention as described hereinabove and as defined in the appendedclaims.

We claim:

1. In a light-tight container comprising a wall defining an interiorchamber for the storage of light-sensitive material, said wall includingan upper and a lower lip, said pair of lips defining an elongated slotthrough the wall for providing a passageway into said chamber for saidmaterial, said passageway having a relatively large width and arelatively small height and length, and a light lock affixed to saidlips for preventing the passagel of light intosaid chamber whileallowing the passage of said material through said passageway, theimprovement wherein said light lock comprises:

an elongated pad comprising a layer of resilient material laminated to alayer of facing material, said facing material having a relatively lowcoefficient of friction, said pad being affixed to said upper lip withthe resilient layer in contact with said upper lip, said pad having alength at least equal to the width of said passageway, said pad having athicknessl greater than half the height of said passageway, said padhaving a width at least as great as the length of said passageway, andsaid facing layer curving toward said upper lip at both of the elongatededges of the pad; and

an elongated flap comprising a layer of resilient material laminated toa layer of facing material, said facing material having a relatively lowcoefficient of friction, said flap being affixed to said lower lip alonga single longitudinal line with the resilient layer in contact with saidlower lip, said line terminating short of the side walls of saidpassageway, said flap having a length at least as great as the width ofsaid passageway, said flap having a thickness greater than half theheight of said passageway, and said pad having a width at least as greatas the length of said passageway.

2. The improvement according to claim l wherein said container wall issubstantially cylindrical and said material is stored in roll form andwherein the inwardly extending edge of said flap extends beyond saidwall and into said chamber.

3. The improvement according to claim 2 wherein said inwardly extendingedge of said flap is hemmed so as to provide a smooth layer of saidfacing material to the outer convolution of the roll of light-sensitivematerial in said container.

4. The improvement according to claim 2 wherein said inwardly extendingedge of said flap is pinched whereby the light-sensitive material as itis withdrawn from said container bridges over said inwardly extendingedge so as to not come into contact therewith.

S. The improvement according to claim l wherein said sin glelongitudinal line of affixation is adjacent the front edge of saidyother of said lips but spaced inwardly a distance therefrom such thatboth of the elongated edges of said flap are free and unattached to saidlower lip.

6. In a light-tight film cartridge of the type comprising a walldefining an interior chamber for the storage of a roll of film, thecontainer wall having an upper and a lower lip, said lips defining anelongated slot providing a passageway through said wall and into saidchamber'for said material, and a light lock for preventing the passageof light into said chamber while allowing thepassage of said materialthrough said passageway, the improvement wherein said light lockcornprises:

an elongated flap comprising a layer of resilient material laminated toalayer 'of facing materialI said facing layer having a relatively lowcoefficient of friction, said flap being affixed to the lower lip', withthe resilient material in contact with the lower lip only along a singlelongitudinal line, said line terminating short of the side walls of thepassageway for allowing said flap to bulge toward the upper lip at bothsides of said passageway, said flap ex tending across the entire heightand width of the passageway to providean effective light lock.

7. The improvement according to claim 6 wherein the inwardly extendinglongitudinal edge of said flap extends into sald chamber beyond theinterior edge of said lower lip.

8. The improvement according to claim 7 wherein said inwardly extendingedge of said flap is hemmed.

vses

